Detailed description of scanning electromagnetic microscope (SEM) of the Holothuria scabra’s ossicles (Holothuroidea: Echinodermata) collected from Pesawaran Waters, Lampung, Indonesia

Abstract

Khatulistiani TS, Dewi AS, Yasman. 2022. Detailed description of scanning electromagnetic microscope (SEM) of the Holothuria scabra’s ossicles (Holothuroidea: Echinodermata) collected from Pesawaran Waters, Lampung, Indonesia. Biodiversitas 23: 3697-3704. Ossicles are microscopic calcified endoskeletons that are unique across sea cucumber species. Furthermore, their integrity is maintained after physical and chemical processes that make them a desired attribute for identification purposes. Understanding ossicle characteristic especially for the sandfish H. scabra juveniles is important during mariculture and prevent fraud due to their high economic value. This study aims to identify wild H. scabra ossicles from Pesawaran Waters, Lampung Province, Indonesia using scanning electron microscopes (SEM) to get more detailed morphology of their ossicles. Seven specimens of H. scabra were collected in Pesawaran, Sari Ringgung and Mutun, around Pesawaran Waters. Morphology identification was carried out by observing the body appearance and tentacles of the specimens as well as measuring their weights and lengths. The observation of the ossicles was performed using a light microscope (LEICA ICC50 HD) at 400x magnification and a SEM (Jeol-JCM6000). The length of the tested specimens was around 140-300 mm and their weight was approximately 99-579 g. These two parameters were found to exhibit positive correlation (R2 = 0.93; R= 0.96; p = 0.000). All observed specimens displayed peltate tentacles (12-22 tentacles) surrounding their mouths. The correlation between length and tentacle numbers was also positive (R2= 0.53; R= 0.73; p = 0.101). The shape of the ossicles consists of six to fourteen-hole buttons, tables, spiny perforated plates from the cloaca, tube foot rods, tentacle rods, dorsal rods, dorsal perforated spiny rods, I shaped and branched rods.